INFINITI QX4 2001 Factory Service Manual

SEF289H
PrecautionsNBEC0005IBefore connecting or disconnecting the ECM harness
connector, turn ignition switch OFF and disconnect nega-
tive battery terminal. Failure to do so may damage the
ECM because battery voltage is applied to ECM even if
ignition switch is turned off.
SEF908W
IWhen connecting ECM harness connector, fasten it
securely with a lever as far as it will go as shown at left.
SEF291H
IWhen connecting or disconnecting pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminal, when connecting pin connectors.
MEF040D
IBefore replacing ECM, perform ªECM Terminals and Ref-
erence Valueº inspection and make sure ECM functions
properly. Refer to EC-127.
SEF217U
IAfter performing each TROUBLE DIAGNOSIS, perform
ªDTC Confirmation Procedureº or ªOverall Function
Checkº.
The DTC should not be displayed in the ªDTC Confirma-
tion Procedureº if the repair is completed. The ªOverall
Function Checkº should be a good result if the repair is
completed.
PRECAUTIONS
Precautions
EC-16

SEF348N
IWhen measuring ECM signals with a circuit tester, never
allow the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
IDo not use ECM ground terminals when measuring input/
output voltage. Doing so may result in damage to the
ECM's transistor. Use a ground other than the ECM
terminals, such as the ground.
SEF099WB
IRegarding model R50, ª-B1º indicates the right bank and
ª-B2º indicates the left bank as shown in the figure.
IBank 1 includes No. 1 cylinder.
Wiring Diagrams and Trouble DiagnosisNBEC0006When you read Wiring diagrams, refer to the following:
IGI-34, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº for power distribution circuit
When you perform trouble diagnosis, refer to the following:
IGI-38, ªHOW TO FOLLOW TEST GROUP IN TROUBLE DIAGNOSISº
IGI-34, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
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PRECAUTIONS
Precautions (Cont'd)
EC-17

Special Service ToolsNBEC0007The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.
Tool number
(Kent-Moore No.)
Tool nameDescription
KV10117100
(J36471-A)
Front heated oxygen
sensor wrench
Rear heated oxygen
sensor wrench
NT379
Loosening or tightening front and rear heated oxy-
gen sensors with 22 mm (0.87 in) hexagon nut
(J44321)
Fuel pressure adapter
and gauge kit
SEF326Z
Checking fuel pressure with pressure gauge
Commercial Service ToolsNBEC0008
Tool name
(Kent-Moore No.)Description
Leak detector
(J41416)
NT703
Locating the EVAP leak
EVAP service port
adapter
(J41413-OBD)
NT704
Applying positive pressure through EVAP service
port
Fuel filler cap adapter
NT653
Checking fuel tank vacuum relief valve opening
pressure
PREPARATION
Special Service Tools
EC-18

Tool name
(Kent-Moore No.)Description
Socket wrench
NT705
Removing and installing engine coolant tempera-
ture sensor
Oxygen sensor thread
cleaner
(J-43897-18)
(J-43897-12)
NT828
Reconditioning the exhaust system threads before
installing a new oxygen sensor. Use with anti-seize
lubricant shown below.
a: J-43897-18 18 mm diameter with pitch 1.5
mm, for Zirconia Oxygen Sensor
b: J-43897-12 12 mm diameter with pitch 1.25
mm, for Titania Oxygen Sensor
Anti-seize lubricant
(Permatex
TM133AR or
equivalent meeting MIL
specification MIL-A-907)
NT779
Lubricating oxygen sensor thread cleaning tool
when reconditioning exhaust system threads.
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PREPARATION
Commercial Service Tools (Cont'd)
EC-19

Engine Control Component Parts LocationNBEC0009
SEF929Y
ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Engine Control Component Parts Location
EC-20

SEF034Z
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ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Engine Control Component Parts Location (Cont'd)
EC-21

SEF584Z
ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Engine Control Component Parts Location (Cont'd)
EC-22

SEF036Z
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ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Engine Control Component Parts Location (Cont'd)
EC-23

Circuit DiagramNBEC0010
MEC939C
ENGINE AND EMISSION CONTROL OVERALL SYSTEM
Circuit Diagram
EC-24

System DiagramNBEC0011
SEF930Y
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ENGINE AND EMISSION CONTROL OVERALL SYSTEM
System Diagram
EC-25